(1) Field of the Invention
The present invention relates to an optical disc from and into which a read and a write can be performed and recording and reproducing methods to record and reproduce data on the optical disc. More specifically, the present invention relates to an optical disc on which video data is recorded, and recording and reproducing methods used for such optical disc.
(2) Description of the Related Art
DVD-RAM (Digital Video Disc-Random Access Memory) has been recently developed in the field of rewritable optical discs. A DVD-RAM is a phase change optical disc with a several-GB capacity that exceeds the conventional limits of around 650 MB.
DVD-RAMs can be used by computers to store various kinds of data. In addition, there are hopes that DVD-RAMs will be used to record AV (audio video) data for audio and video. While common conventional recording devices such as video tape recorders (VTRs) record audio and video onto a magnetic tape, there are hopes that such recording will be performed by optical disc recorders that use optical discs.
An optical disc recorder/player that can be used in place of a standard VTR receives a TV (television) broadcast, converts (compresses) a TV signal in the received broadcast into digital AV data, and records the digital AV data onto a DVD-RAM. When reproducing the AV data, the optical disc recorder/player reads the AV data from the DVD-RAM, converts the read AV data into an analog AV signal, and outputs it to a display unit. The generated AV data conforms to MPEG (Motion Picture Expert Group) prescribed in ISO/IEC 13818 (International Standardization Organization/International Electrotechnical Commission).
With some recent analog TV broadcasts, digital data is multiplexed into a TV signal during a vertical blanking interval (hereafter called xe2x80x9cVBIxe2x80x9d, with the digital data multiplexed during a VBI being called xe2x80x9cVBI dataxe2x80x9d). In teletext broadcasting, for instance, text data is multiplexed as VBI data during VBIs.
In a TV (or video) signal conforming to NTSC (National Television System Committee) system, one frame (i.e., two fields) is composed of 525 horizontal scanning lines, and VBI data can be multiplexed during a period that corresponds to the tenth to twenty-first horizontal scanning lines during a VBI and a period that corresponds to the 273rd to the 284th scanning lines during a VBI.
In addition to text data, VBI data can be information such as letterbox control information and copy control information. The letterbox control information is used to control display of an image with an aspect ratio of 4:3 on a display screen with an aspect ratio of 16:9 or 14:9. The copy control information shows whether VTRs are permitted to record the images. A method to multiplex such information as VBI data is defined, for instance, in Journal of the Institute of Television Engineers of Japan vol. 49 No. 9 (1995), and ETS300 294 (European Telecommunications Standards) xe2x80x9cTelevision Systems 625-Line Television Wide ScreenSignaling (WSS)xe2x80x9d.
The letterbox control information and the copy control information are multiplexed into a program or a commercial. As the VBI data can be multiplexed into each field, it is possible to change, for instance, display and copy protection settings only for a certain commercial by multiplexing VBI data into the certain commercial. More specifically, it is possible to change an aspect ratio of a display image and/or allow copying only for commercials by multiplexing appropriate VBI data during the commercial periods.
VTRs for S-VHS (Super Video Home System) are capable of recording a TV signal including VBI data onto a magnetic tape, reproducing the TV signal, and having the TV signal displayed on a display unit. This allows the display unit to recognize the multiplexed VBI data such as letterbox control information and to control the displaying of a letterbox image in synchronization with the TV signal.
However, when a conventional optical disc recorder/player receives the TV broadcast, encodes an analog TV signal in the broadcast into compressed digital data, and records the compressed data onto an optical disc, any VBI data in the TV signal will be lost. As a result, the conventional optical disc recorder/player cannot change the display style or copying permission during fifteen or thirty-second commercial periods when reproducing AV data from an optical disc.
The present invention aims to provide an optical disc, an optical disc recorder, an optical disc player, an optical disc recording method, an optical disc reproducing method that can effectively use VBI data multiplexed into a video signal.
The above object can be achieved by an optical disc of on which at least one video object is recorded. Each video object contains at least one video object unit, and each video object unit contains control information and video data, and has a presentation time of one second or shorter. The control information relates to at least one of: (a) display control for the video object unit; and (b) copying control for the video object unit.
The above object can be also achieved by an optical disc recorder that records a video object onto a recordable optical disc, including: an extracting unit for extracting data that has been multiplexed into an audio-video signal, the data relating to at least one of: (a) display control; and (b) copying control; an encoding unit for encoding the audio-video signal to generate the video object containing at least one video object unit that has a presentation time of one second or shorter; an generating unit for generating, based on the extracted data, control information relating to at least one of: (a) display control for each video object unit in the video object; and (b) copying control for each video object unit in the video object; and a controlling unit for having the encoding unit to insert the generated control information into each video object unit.
The above object can be also achieved by an optical disc player that reproduces a video object recorded on an optical disc, the video object containing at least one video object unit that each has a presentation time of one second or shorter. The optical disc player includes: a reading unit for reading the video object from the optical disc; a separating unit for separating each video object unit in the read video object into video data, audio data, and control information; a decoding unit for decoding the video data and the audio data obtained by separating the video object unit to generate an audio-video signal corresponding to the video object unit; and a multiplexing unit for multiplexing additional data into the generated audio-video signal during vertical blanking intervals based on the control information that has been obtained by separating the video object unit.
Here, each video object may be generated from an analog video signal, and control information may indicate a content of data that is multiplexed into vertical blanking intervals in the analog video signal.
Here, the control information may show at least one of: (a) a display position for the video object unit; (b) copying management conditions for the video object unit; and (c) a source-material type for the video object unit.
With this construction, each video object unit contains control information, therefore, display control and copying control can be achieved for each video object unit, which is to say, different display and copying control can be performed for every second or lower. This enables the change of, for instance, a display style or copying permission during a certain period, such as a commercial, of a program.
Here, each video object unit may contain one control pack and a plurality of video packs into which video data is placed. The control pack may be placed at a start of the video object unit and contains the control information.
For this construction, a control pack is located at a start of each video object unit. This simplifies an operation by an optical disc recorder to insert a control pack into each video object unit, and so can reduce the operation load of the optical disc recorder.
Here, the control information may further contain status information showing which parts of the control information are valid.
As control information additionally contains status information, it becomes possible to insert a video object unit having valid information regarding display and copying control and a video object unit having invalid information regarding display and copying control into the same video object.
Here, the control information may contain letterbox control information that shows a display position of images for the video object unit on a screen.
For this construction, an optical disc player can perform letterbox control for each video object unit, that is, for every second or lower.
Here, the control information may show an aspect ratio of images for the video object unit.
For this construction, an aspect ratio can be set, for each video object unit, in control information.
Here, the control information may contain subtitle mode information showing a display position of subtitles for the video object unit.
This allows an optical disc player to control a display position of a subtitle for each video object unit. Here, the control information may contain film/camera mode information that shows whether a source material of the video object unit was recorded either by a television camera or on a movie film.
For this construction, film/camera mode can be set, for each video object unit, in control information.
Here, the control information may contain information regarding Copy Generation Managing System to show whether to permit the video object unit to be copied onto another recording medium.
With this construction, information regarding Copy Generation Management System can be set, for each video object unit, in control information.
Here, the control information may contain information regarding Analog Protection System (APS) to show a type of APS copy protection method used on an analog video signal based on which the video object unit was generated.
With this construction, information regarding Analog Protection System can be set, for each video object unit, in control information.
Here, the control information may contain source information that shows whether a source material of the video object unit is an analog pre-recorded package medium.
With this construction, source information can be set in control information for each video object unit.
Here, in addition to at least one video object that contains control information, at least one piece of stream information and a video object that contains no control information may be recorded on the recordable optical disc. Each piece of stream information may be associated with at least one video object, and contain: aspect information that shows an aspect ratio of the at least one video object associated with the piece of stream information; and an application flag that shows either: (a) that the video object is encoded using the aspect ratio in the aspect information; or (b) that the video object is not necessarily encoded using the aspect ratio in the aspect information, and an aspect ratio in control information in each video subject unit is used.
As this stream information is recorded separately from each video object, an optical disc player can obtain an aspect ratio in the stream information for each video object unit without needing to read the video object if an application flag is shown as xe2x80x9c00bxe2x80x9d. In this way, the optical disc player can judge whether an aspect ratio of a video object or of each video object unit should be used for the video object, using the application flag. In addition, a size of a video object that contains no control information can be reduced by the size of this control information.
The above object can be also achieved by a recording to record a video object containing at least one video object unit onto an optical disc, including: an extracting step for extracting data that is multiplexed into an audio-video signal, the data relating to display control and copying control; an encoding step for encoding the audio-video signal to generate video data and audio data; a generating step for generating control information that relates to display control and copying control based on the extracted data; and a multiplexing step for multiplexing the control information, the video data, and the audio data that have been generated, into a video object unit having a presentation time of one second or shorter.
The above object can be also achieved by a reproducing method to reproduce a video object recorded on an optical disc, including: a reading step for reading the video object from the optical disc, the video object containing at least one video object unit that each has a presentation time of one second or shorter; a separating step for separating each video object unit in the read video object into video data, audio data, and control information; a decoding step for decoding the video data and the audio data obtained by separating the video object unit to generate an audio-video signal corresponding to the video object unit; and a multiplexing step for multiplexing additional data into the generated audio-video signal during vertical blanking intervals based on the control information that has been obtained by separating the video object unit.
The above object can be also achieved by a program that is recorded on a computer-readable recording medium and that has a computer perform a recording operation to record a video object containing at least one video object unit onto an optical disc. The recording operation includes: an extracting step for extracting data that is multiplexed into an audio-video signal, the data relating to display control and copying control; an encoding step for encoding the audio-video signal to generate video data and audio data; a generating step for generating control information that relates to display control and copying control based on the extracted data; and a multiplexing step for multiplexing the control information, the video data, and the audio data that have been generated into a video object unit having a presentation time of one second or shorter.
The above object can be also achieved by a program that is recorded on a computer-readable recording medium and that has a computer perform a reproducing operation to reproduce a video object recorded on an optical disc. The reproducing operation includes: a reading step for reading the video object from the optical disc, the video object containing at least one video object unit that each has a presentation time of one second or shorter; a separating step for separating each video object unit in the read video object into video data, audio data, and control information; a decoding step for decoding the video data and the audio data obtained by separating the video object unit to generate an audio-video signal corresponding to the video object unit; and a multiplexing step for multiplexing additional data into the generated audio-video signal during vertical blanking intervals based on the control information that has been obtained by separating the video object unit.